Most optical transmission systems are capable of monitoring a received power of an optical signal over long periods of time such as days, hours or minutes. These conventional optical transmission systems use dedicated components to perform the monitoring of the power of a received optical signal transmitted through an optical fiber of said optical network. However, these conventional optical transmission systems have no technical means to detect short-term unusual or uncharacteristic changes in the received optical power levels. By tapping an optical signal transported through an optical fiber a third party might intentionally bend the optical fiber to extract the optical signal. This manipulation or intrusion causes uncharacteristic short-term power level changes of the optical signal transmitted through the optical fiber.
To increase security of the optical transmission system there is a need to provide a cost-effective way to monitor and to detect unusual or uncharacteristic short-term and/or long-term power level changes in the power level of the received optical signal which may indicate fiber plant trouble or intrusions without requiring additional optical signals, specialized receivers, equipment or specialized components dedicated to the measurement of short-term power level changes.